Supporting and spacing means for electrodes in discharge tubes



Oct. 13, 1936. ROTHE 2,057,115

SUPPORTING AND SPACING MEANS FOR ELECTRODES IN DISCHARGE TUBES Filed Feb. 2, 1934 INVENTOR HORST 07/15- ATTORNEY Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE SUPPORTING AND SPACING MEANS FOR ELECTRODES IN DISCHARGE TUBES Germany Application February 2, 1934, Serial No. 709,446 In Germany February 6, 1933 4 Claims.

The present invention is concerned with an advantageous form of construction of the insulating parts customary for the supporting and the spacing of electrodes in discharge tubes.

At the present time, in assembling the electrode system of a discharge tube recourse is often had to insulation parts consisting of ceramic material or mica which hold the supporting stays to which the electrodes are fastened in proper spaced relation. Such means for support is provided either at both ends of the electrode system or else only at the end remote from the squash or press. During operation of the tube, part of the active cathode material is caused to disintegrate and becomes deposited upon insulating parts in the form of a thin conducting coat which tends to impair the insulation between the various electrodes and gives rise to the fiow of creepage or leakage currents. Hence, to eliminate this defect, it has been found advantageous to subdivide these various insulations and to stagger them so that several insulation parts, each of which supports a group of electrodes, are disposed in different planes and held together by distinct connecting elements. In this manner the insulation distance between attachment points of adjacent electrodes is enlarged and thereby the preservation of the requisite high insulation resistance is insured.

According to this invention the various insulation parts, prior to their assembly with the electrodes, are united to form one construction unit. A very simple connection results from the use of what is called tubular rivets, i. e., short metallic bushings which are pushed through holes placed so as to register and which are then crimped around their edges. If desired, spacer pieces may be placed between the various plates in order that the distance between them may be enlarged.

One exemplified embodiment is illustrated in the drawing. The electrode system consists of the indirectly heated cathode K, a control grid G and the plate A; plate and grid are attached to the supporting wires Sc and So, respectively. The insulation pieces M and M" which serve to support and insure proper spacing, are held together by tubular rivets N, with spacer pieces D being interposed with a View to increasing the distance therebetween.

If desired, the various spacer members may be made of different materials; for instance, the inner part M may consist of some ceramic substance, and the outer one M', of mica. The use of insulation parts thus staggered is recommendable both with triode tubes in which for the purpose of insuring high mutual conductance values (slopes) the electrodes are mounted at close proximity, as well as, and more particularly so, in tubes furnished with a greater number of electrodes.

What is claimed is:

1. An electron discharge tube comprising a press, a cylindrical cathode mounted above the press, cylindrical grid and anode electrodes surrounding the cathode, parallelly arranged support rods for said electrodes having their lower ends sealed into the press, an annular disc of insulating material disposed transversely to the electrode axis and having openings within which are snugly fitted the upper ends of the anode support rods, a circular disc of insulating material arranged in overlapping relation with respect to the inner edge portion of the annular disc and having openings within which are snugly fitted the upper end of the cathode and the upper ends of the grid support rods, and means for rigidly uniting said discs in overlapping relation.

2. An electron discharge tube comprising a plurality of electrodes, supports for said electrodes, an annular insulating disc having openings within which snugly fit the ends of certain electrode supports, a circular insulating disc having openings within which snugly fit the ends of certain other electrode supports, said discs being disposed in difierent planes, and means for rigidly interconnecting the periphery of the circular disc with the inner periphery of the annular disc.

3. An electron discharge tube comprising at least an anode and a grid, support rods therefor, an annular insulating disc having openings within which snugly fit the upper ends of the anode support rods, a circular insulating disc having openings within which snugly fit the upper ends of the grid support rods, said discs being disposed in different planes, and means for rigidly interconnecting the periphery of the circular disc with the inner periphery of the annular disc.

4. The invention defined in the preceding claim wherein spacing means are provided between the mentioned disc peripheries to which they are joined by the interconnecting means.

HORST RO'IHE. 

